In some ways, so far, Yosemite reminds me much of Mountain Lion. A 'refining' of the Mac experience. ML refined what Lion left agape, just as Yosemite refined what Mavericks messed up/skipped. An example is Time Machine - in Mavericks, for some reason, no matter which folder you were in when you entered Time Machine, the window would just jump to your ~/ folder. Very annoying! Despite me reporting this, and this being prevalent through the entire DP's/actual builds of Mavericks (10.9.0-.5), Apple didn't fix it. They fixed it in Yosemite. Another example is adding back 3-finger swipe in Finder (which existed in ML, but was removed in Mavericks). Overall, the whole experience just feels much smoother and polished. I remember 10.8.0 as being a VERY smooth x.0 release of OS X (when, traditionally, other x.0 releases had issues/glitches). 10.9.0 was the opposite - don't even want to go there again. So far, even though it's only been a day and an half, I'm REALLY liking Yosemite so far. Oh, and when upgrading from SL to Mavericks, with multiple user accounts, wallpapers didn't stick after the upgrade to Mavericks. They were preserved just fine with ML and Yosemite. Another example of how sloppy Mavericks was. General conventional wisdom is to be cautious with the odd versions of OS X (10.5/10.7/10.9), and to look at the even versions (10.6/10.8/10.10) as more reliable/trustworthy. A little, somewhat irrelevant, but still cute detail, is that ML was named after a mountain lion. Yosemite is also a big mountain. Just another way both OS'es come across as similar. What do y'all think?